Caffeine May Slow Cognitive Decline in Women

MONTPELLIER, France, Aug. 8 -- Drinking more than two cups of coffee a day may slow cognitive decline in older women, but coffee did not reduce the risk of dementia, researchers found.
In a study of men and women 65 or older who were dementia-free at baseline, women who drank at least two cups of coffee a day were 18% less likely to develop problems with verbal recall (P=0.05), said Karen Ritchie, Ph.D., of INSERM, the French National Institute for Health and Medical Research, here, and colleagues.
And those who drank more than three cups of coffee were 33% (P=0.0005) less likely to develop memory problems, they reported in the Aug. 7 issue of Neurology.
No similar benefit was observed for men, the researchers said, and there was no relationship between caffeine intake and incident dementia from all causes (P=0.76) or Alzheimer's disease (P=0.96).
Moreover, there was no significant protection for women who consumed less than 200 mg of caffeine daily, which the authors equated with two cups of coffee or four cups of tea.
From 1999 through 2001 the researchers recruited almost 9,077 men and women living in Bordeaux, Dijon, and Montpellier for a prospective population-based study. Coffee and tea consumption was ascertained from structured baseline interviews. The participants were followed for four years.
Cognitive function was assessed with three standard measures: the Mini-Mental State Examination, the Benton Visual Retention Test (a test of visuospatial recall), and the Isaacs Set Test (a test of verbal recall and fluency).
After a mean follow-up of 3.47 years, data from 4,197 women and 2,820 men were available for analysis. The mean age of the participants was 74.
Among the findings:
Women consumed more caffeine than men, with 16.4% of women consuming more than 3 cups of coffee a day versus 13.2% of men (P=0.0006).
Twenty percent of participants ages 65 to 69 drank more than three cups of coffee a day, but only 10% of participants over 80 drank that much.
People who had at least nine years of education drank more coffee than those who had attended school for five years (P=0.0001).
Compared with people who had never smoked, current smokers were 3.7 times more likely to drink more than three cups of coffee daily and former smokers were 2.26 times more likely to consume at least three cups of coffee daily (P=0.0001).
Dr. Ritchie said in a statement that caffeine was a "pyschostimulant", but she added, the exact mechanism for the apparent protective effect is not known.
Noting that the benefit was observed only in women, the authors speculated that the difference could indicate that women are more sensitive to the effects of caffeine than men, perhaps because of "pharmacodynamic or caffeine metabolism differences."
Other possible explanations, they wrote, were the possibility that older women "are more susceptible to the cholinergic properties of caffeine than men" or that there is a "positive association between caffeine intake and estrone, or sex hormone-binding globulin levels."
The authors said the study was limited by the possibility that "selective attrition could have promoted a healthy survivor effect on the remaining sample." Additionally, the researchers did not consider the type of coffee or tea consumed (filtered, instant, brewed, black or green tea).
The authors said if caffeine does slow the progression of dementia it might take longer than four years to evaluate the risk.
Finally, the authors concluded, although it may be tempting to recommend coffee or tea as a widely available tonic for the aging brain, "biologic evidence clarifying the relationship between caffeine use and neural degeneration is required before the instigation of a public health program promoting caffeine intake may be recommended."
The study was funded by INSERM, the Victor Segalen-Bordeaux II University, Sanofi-Synthélabo, the Fondation pour la Recherche Médicale, Caisse National Maladie des Travailleurs Salariés, Direction Générale de la Santé, MGEN, the Institut de la Longévité, Agence Française de Sécurité Sanitaire des Produits de Santé, the regional governments of Aquitaine, Bourgogne, and Languedoc-Roussillon, and the Fondation de France, the Ministry of Research-INSERM Programme "Cohorts and collection of biological material."
The authors reported no conflicts of interest.Primary source: NeurologySource reference: Ritchie K et al "The neuroprotective effects of caffeine A prospective population study (the Three City Study)" Neurology 2007; 69:536-545.